US 2006/0021735 A1 describes a cooling unit in which a heatsink is integrated in a radial blower. The heatsink comprises a base and heat exchanging means talking the form of spiral cooling fins or cooling pins. The impeller surrounds the heatsink coaxially. A drive motor is designed as a motor with disk-shaped rotor, the rotor being integrated in the impeller and an annular arrangement of stator coils lying opposite to the rotor in an axial direction. The impeller has a large central opening, the stream of air flowing through this central opening in an axial direction towards the cooling fins of the heatsink and from there being conducted in a radial direction over the blades of the impeller and through a lateral outlet. According to this document, it is advantageous to use a motor with disk-shaped rotor rather than a radial flux machine having a hub drive, because in this way the air stream can pass through the central space within the impeller without obstruction of any part of the motor. However, the use of motors with disk-shaped rotors has the disadvantage that the flat coils used for the stator are restricted with respect to the number of their windings and they can only draw a limited amount of current, making them generally less efficient than radial flux machines. In addition, the cooling effect of the cooling unit according to US2006/0021735A1 is not optimal due to the construction of the heatsink and the almost total inclusion of the heatsink in a housing, where only one outlet is open.
U.S. Pat. No. 7,044,202 B2 describes a cooling apparatus for electronic components having a radial flux machine and a central cylindrical hub member that is used to draw off heat from the electronic components. The hub is provided with curved cooling fins and is enclosed by an impeller that has fan blades curved in the same direction. The hub member is relatively voluminous so that only limited space is available for the airflow. In the cooling apparatus of U.S. Pat. No. 7,044,202 B2, air is drawn in an axial direction from both sides and exhausted in a radial direction. The arrangement according to this document seems to be relatively voluminous, so that in relation to its volume, low efficiency is to be expected.
U.S. Pat. No. 7,021,894 B2 describes a cooling apparatus having a heatsink (that essentially has a base and a plurality of cooling pins. These cooling pins are disposed about an annular space, an impeller rotating in the annular space. The impeller is driven by a disk rotor motor.
US 2002/0062947 A1 describes a cooling apparatus that has a similar construction to the cooling apparatus of U.S. Pat. No. 2,021,894 B2, the cooling apparatus being driven, however, by a radial flux machine that is disposed at the center of the impeller. A similar prior art is described in U.S. Pat. No. 6,244,331 B1.
In general, the present invention relates to a cooling system for controlling or regulating the temperature of an electronic device that is to be cooled, and particularly for cooling hot spots on CPUs, memories or power semiconductors such as transistors or LEDs, graphic processors and other processors that are preferably employed in compact and/or mobile electronic appliances such as mobile telephones, PDAs, electronic organizers, navigation systems, mini-laptops and mobile miniature memories.
The removal of surplus, function-critical heat or its reduction to a non-critical level is a key consideration in the design and utilization of many electronic devices. Along with the reduction in size of electronic components and the increase in their performance, there is a rise in the amount of heat generated. Furthermore, modern processors may have increased power consumption and also increasingly efficient electronic power components are being launched on the market. Since these kinds of components are often tightly packed together in increasingly small electronic appliances, the effective cooling of these components using highly efficient, miniaturized cooling devices is a crucial factor in the development of electronic equipment. At the same time it is not only necessary for the cooling device to be small and efficient but it should have a low energy consumption and heat development as well.
As mentioned above, electrically driven blowers having integrated heatsinks for the purpose of cooling electronic components are known in the prior art. An object of the present invention is to improve known cooling devices with respect to their efficiency, while the overall cooling device remains as small and flat as possible and the conduction of the flow of air being optimized.